Return spring bumper for print hammers



Jan. 19, 1965 J. FRADKIN 3,166,010 RETURN SPRING BUMPER FOR PRINT HAMMERS Filed May 3, 1962 INVENTOR Jose-PH Rum w ATTORNEY United States Patent Joseph Fradkin, Plainview, N.Y., assignor to Potter Instrument Company, Inc., Plainview, N.Y., a corporation of New York Filed May 3, 1962, Ser. No. 192,251 3 Claims. (Cl. 101-93) This invention, generally, relates to high speed printer apparatus and, more particularly, to a new and improved structural arrangement for a hammer module in such apparatus.

In apparatus to which the invention is uniquely adapted to operate, it is customary to provide return bias force on each hammer so that each hammer is retracted to a non-printing position with as much speed as possible. Heretofore, the most desirable return biasing force has been provided by a leaf spring, but disadvantages developed by such a spring have directed most applications to the use of coil springs.

It is a primary object of the invention to provide a new and improved structural arrangement for a printer module in a high speed printer apparatus which admits of ready use of leaf spring means to bias the hammer in a retracted, non-printing position.

It is also an object of the invention to provide improved hammer return means for a high speed print hammer.

Briefly, a high speed printer apparatus in accordance with the invention includes print hammers adapted to be actuated at rapid rates to effect a printing operation. Means as provided to energize each hammer in the apparatus for movement in a predetermined manner to effect a printing action, and a hammer return means, in accordance with the invention, is provided to return the hammer to a retracted, non-printing position. This hammer return means includes a first and second resilient means at least one of which is fixedly attached with the hammer so that no relative motion is developed between the hammer return means and the hammer.

The above and other advantages of the invention will become apparent from the following detailed description of a preferred form thereof taken in conjunction with accompanying drawings, in which:

FIG. 1 is a diagrammatic View illustrating the principal component parts in accordance with the invention;

FIG. 2 is an enlarged fragmentary view of a portion of FIG. 1; and

FIG. 3 is a view similar to FIG. 2 showing therein a hammer not in accordance with the invention.

Referring now to FIG. 1 of the drawings, the numeral identifies, generally, a single hammer of a plurality of hammers adapted to operate in a high speed printer apparatus, the hammer having a main body portion 11 and a hammer head 12 with a type striking surface 13. The hammer body 11 is supported for oscillatory movement about an axis 14.

A suitable electromagnetic 15 includes a core 16 and a winding 17 with input terminals 18 and 19. Upon energization of the magnetic 15, the end 20 of the hammer body 11 is rotated counterclockwise about the axis 14 so that the type striking surface 13 is moved to the left as viewed in FIG. 1 to strike a type. Upon de-energization of the magnetic 15, the hammer body 11 is returned to a retracted, non-printing position by rotation in a clockwise direction about the axis 14 under the action of a spring bias indicated generally by the numeral 21.

A stop 22 is provided by a threaded screw 23 with a head 24 and an end 25 against which the hammer head 12 m V CC rests. The screw 23 is threaded in a suitable support 26 for adjustment to alter the position of the stop. 7

The hammer return means 21 is provided by a leaf spring 27 one end of which is attached through a fixed block 28 to a fixed reference surface 29 by means of two screws 30 and 31.

The leaf spring 27 is arcuate to form a tension against the body portion 11 tending to rotate the body portion 11 in a clockwise direction about the axis 14. The end 32 of the spring 27 is curved in an arcuate manner so that a smooth curved surface is presented at a point of relative movement between the leaf spring 27 and a bumper pad indicated generally by the numeral 33.

The pad 33 is formed of a resilient material such as rubber or plastic and while the pad 33 may be fixedly attached to the body portion 11 of the hammer and to the spring 21, so that all motion is experienced within the resilient pad 33. FIG. 2 of the drawings shows the arcuate end 32 resting against the bumper 33 and all relative movement between the hammer return means 21 and the hammer body portion 11 occurs along a line indicated by the arrow 34.

In FIG. 3 of the drawings, a hammer body portion 11' is shown with a leaf spring 27' without a bumper disposed therebetween. As indicated by the arrow 35, the arcuate end 32 has worn an arcuate groove in the body portion 11 thus altering the magnitude of the bias force provided by the leaf spring 27 In accordance with the present invention, no movement is developed between the hammer return means 21 and the hammer body portion 11, thus preventing any change in magnitude of the hammer return force.

A further advantage of the return spring bumper in accordance with the invention, is that any tendency of the hammer to bounce during rapid operation is absorbed in the resilient bumper 33.

While the above description is directed to a presently preferred embodiment, it will be understood that the invention will be limited by the scope of the appended claims.

What is claimed is:

1. In a high speed printer apparatus including print hammers adapted to be actuated at rapid rates to effect a printing operation, each hammer comprising,

a main body portion adapted to be pivoted about a predetermined axis intermediate of its ends,

one end of the body portion having a hammer head with a surface adapted to strike a print type,

electromagnetic means positioned adjacent the hammer body portion on the opposite side of the pivot means from the hammer head and including energization means whereby the hammer may be pivoted in a predetermined manner upon the excitation of the electromagnetic means,

a hammer stop positioned adjacent the hammer head to limit the retracted, non-printing position of the hammer head when the electromagnetic means is de-energized,

a leaf spring having one end fixedly attached to a reference surface and the opposite end disposed in an arcuate manner in the direction of the body portion of the hammer, and

a resilient pad fixedly attached to the hammer body portion on one surface and having the opposite surface in abutting relation to the opposite end of the leaf spring and in sliding relation therewith.

2. In a high speed printer apparatus including print hammers adapted to be actuated at rapid rates to effect a printing operation, each hammer comprising,

a main body portion adapted to be pivoted about a predetermined axis intermediate of its ends, one end of the bodyportion having a hammerhead with a surface adapted to strike a print type,

hammer actuating means including energization means whereby the hammer body portion may be pivoted in a predetermined manner to cause the hammer head surface to'move from a retracted non-printing position toward an impact printing position,

a hammer stop positioned adjacent the hammer head to limit the retracted non-printing position of the hammer head when the hammer actuating means is de-energized,

spring means having one end fixedly attached to a reference surface and the opposite end disposed in the direction of the body portion of the hammer to develop a predetermined biasing force tending to move the hammer head toward the hammer stop, and

a resilient pad fixedly attached to the hammer body portion on one surface and having the opposite surface in abutting relation to and in free sliding engagement with the opposite end of the spring means.

3. In a high speed printer apparatus including print hammers adapted to be actuated at rapid rates to eifect a printing operation, each hammer comprising,

a main body portion adapted to be pivoted about a predetermined axis intermediatee of its ends,

one end of the body portion having a hammer head with a surface adapted to strike a print type,

hammer actuating means including energization means whereby the'hammer body portion may be pivoted in a predetermined manner to cause the hammer head surface to move from a retracted non-printing position toward an impact printing position,

spring means having one end fixedly attached to a reference surface and the opposite end portion disposed in the direction of the body portion of the hammer to develop a predetermined biasing force tending to move the hammer head toward the hammer stop, and a resilient pad supported between the opposite end portion of the spring means and the hammer body portion and in free sliding engagement with at least one of said last-mentioned two portions.

References Cited by the Examiner UNITED STATES PATENTS 576,284 2/97 Stickney 197--29 576,285 2/97 Stickney 197-29 576,329 2/97' Stickney 19729 779,425 1/0 5 Howell 19733 950,029 2/10 Roberts 197-33 967,915 8/10 Hess et al. 197-33 2,405,562 8/46 Ellerbeck 101-109 X 2,686,470 8/54 Gore et a1. 10193 2,766,686 10/56 Fomenko et al. 10193 2,805,620 9/57 Rosen et a1 101-93 3,041,964 7/62 Simpson et a1 101-93 OTHER REFERENCES IBM Technical Disclosure Bulletin, volume 4, No. 11, April 1962.

WILLIAM PENN, Primary Examiner. 

1. IN A HIGH SPEED PRINTER APPARATUS INCLUDING PRINT HAMMERS ADAPTED TO BE ACTUATED AT RAPID RATES TO EFFECT A PRINTING OPERATION, EACH HAMMER COMPRISING, A MAIN BODY PORTION ADATED TO BE PIVOTED ABOUT A PREDETERMINED AXIS INTERMEDIATE OF ITS ENDS, ONE END OF THE BODY PORTION HAVING A HAMMER HEAD WITH A SURFACE ADAPTED TO STRIKE A PRINT TYPE, ELECTROMAGNETIC MEANS POSITIONED ADJACENT THE HAMMER BODY PORTION ON THE OPPOSITE SIDE OF THE PIVOT MEANS FROM THE HAMMER HEAD AND INCLUDING ENERGIZATION MEANS WHEREBY THE HAMMER MAY BE PIVOTED IN A PREDETERMINED MANNER UPON THE EXCITATION OF THE ELECTROMAGNETIC MEANS, A HAMMER STOP POSITIONED ADJACENT THE HAMMER HEAD TO LIMIT THE RETRACTED, NON-PRINTING POSITION OF THE HAMMER HEAD WHEN THE ELECTROMAGNETIC MEAN IS DE-ENERGIZED, A LEAF SPRING HAVING ONE END FIXEDLY ATTACHED TO A REFERENCE SURFACE AND THE OPPOSITE END DISPOSED IN 